Shoe with a removable interchangeable heel and variable curvature

ABSTRACT

The shoe with removable heel comprises an insole ( 1 ) and a removable heel ( 2 ) arranged to be securely assembled and in separable manner with a rear part ( 11 ) of the insole. The heel is connected to a shank ( 4 ) extending along a longitudinal direction of the insole and engaging with guide means located in said central part ( 12 ) and secured to the insole, the shank having a predetermined longitudinal profile so as to adapt to the curvature of the insole in said central part according to the height of the heel and the guide and retaining means ( 51, 321 ) are concealed by a central part of the sole ( 9 ).

BACKGROUND

The invention relates to shoes with removable heels and variable curvature of the waist of the shoe, more especially ladies shoes with a totally removable and interchangeable heel which can be simply and quickly removed and reinstalled without the need for tools. The aim of the invention is notably to allow the heel to be easily changed to adapt the height of the shoe according to the needs whilst conserving the same footwear, which therefore also requires an adaptation of the curvature of the waist of the shoes (“curvature” herebelow).

It is recalled that a shoe generally comprises three parts:

-   -   the upper which consists of the apparent upper part and its         inner lining and any reinforcements,     -   the insole, consisting of several layers, onto which the upper         is attached, generally by gluing and/or sewing and which, thus         assembled with the upper and completed by the whole length sock         which covers the insole, determines the interior volume         accommodating the foot,     -   the sole which is attached under the insole generally over the         complete surface of the insole, inserting between them the lower         edge of the upper in part folded under the insole.

The heel, towards the rear of the shoe, is generally attached under the sole or integrated into it. Therefore, most often, only the front part of the sole is in contact with the ground, the heel ensuring the contact with the ground at the rear of the shoe, and an intermediary part of the sole, between the front part and the heel, is raised and normally not in contact with the ground.

The heel plays an undeniable aesthetic role, mainly for high heel shoes for women. In addition, the heel also meets a need for stability and help in walking. The heel is most often made from hard plastic materials and is resistant to shocks and compressions (ABS or polystyrene).

The insole is something as a chassis of the shoe and, in order to reinforce the stiffness of this chassis, a shank, or shank, is often used. This is a rigid part formed according to the required curve of the insole and attached to it at the level of the plantar arch. The intermediary part of the sole is located substantially at the same level. The shank avoids a deformation of the profile curvature of the waist of the shoe, and therefore provides good support of the rear part of the foot and good stability of the heel. The shank can be made of steel, wood or of rigid plastic, according to the type of shoe, its use and the height of the heel.

Shoes with removable heels have been known for a long time, generally intended to allow the use of various heels adapted to the use planned for the shoes. For example, U.S. Pat. No. 2,795,866 describes a shoe with replaceable heel, where the heel is assembled with the upper by a slide system placed under the insole and with a lock to block the heel on said slide.

Shoes with removable heels, designed to allow the use of different heights of heels with the same upper, are also known. On account of these various heel heights, a shank with a curve adapted to this height is provided for each heel height.

Thus, US2006075662 shows a shoe with a removable heel, where the heel is formed in one part with the shank, the shape of which is adapted to the height of the heel. The rear part of the insole, plumb with the heel, is pivoting in relation to the front part of the insole and includes a boss adapted to be inserted into a housing provided at the upper end of the heel. Moreover, a longitudinal housing is made in the insole, or between the insole and the sole, to accommodate the shank. To put the heel in place, the shank is inserted into said longitudinal housing, then the rear pivoting part of the insole is folded to insert the boss into the housing of the heel until it is clicked in by a lock spring. This system therefore requires an insole with a rear hinged part, which can create discomfort at the hinge and, in addition, is detrimental to the good stiffness of the junction, especially in torsion, between the front part of the shoe and the heel, as only the shank ensures this junction. Also again, it is the hinge of the insole which must alone support all of the loads liable to be exerted in the longitudinal direction between the front part and the heel. And, lastly, the need for the pivoting movement of the rear part of the insole, with the rear part of the upper, implies that the upper must be adapted to allow said pivoting.

US20070256330 also shows a shoe with a removable heel, wherein the heel is hinged on the shank which is inserted into a housing made in a flexible member placed under the upper of the shoe, then the heel is locked on a rear part of said flexible member. To allow for the insertion of the shank, said flexible member is thickened in the intermediary and rear parts, and to allow the bending of the thickened intermediary part, according to the possible various curvatures, this thickened part is notched to provide it with a required deformation capability. A disadvantage of such a shoe is that the overthickness formed by this flexible member is highly visible in the intermediary part and rear part of the shoe, which is detrimental to the aesthetics of the shoe. Another disadvantage is that the notches are visible under the shoe and are also detrimental to the aesthetics. Another further disadvantage is that the curvature is determined by the bending of this flexible member, at a relatively low level, and therefore far from the upper face of the insole, which can lead to a lack of stiffness at this upper surface on which the user's foot bears.

SUMMARY

The object of the invention is to solve the problems mentioned above and particularly aims at proposing a shoe retaining a marked aesthetic appearance, in spite of the means implemented to allow its adaptability to various heel heights. It also aims at providing a shoe with a removable heel with the same comfort as a conventional shoe, irrespective of the height of the heel used. And it again aims at proposing a new assembly system for a removable heel on a shoe, which is simple and fast to use, the replacement of a heel by another one being practically possible without the need to take off the shoe.

With these targets in mind, the object of the invention is a shoe with a removable heel comprising

-   -   an insole and an upper attached to the insole, the upper having         a flexible central part so that its curvature can be adapted to         the height of the heel,     -   a removable heel, the latter being arranged so that it can be         attached under a rear part of the insole and form with said rear         part a separable rigid assembly,     -   a sole attached under the insole forward of the heel, to cover a         ground support front part of the insole and comprising a rear         part to cover a central part of the insole, located between the         front part and the heel.

Moreover, the heel is connected to a shank extending along a longitudinal direction of the insole and engaging, without significant play transversally to said longitudinal direction, with guide and retaining means located in the central part of the insole and attached to it, the shank having a predetermined longitudinal profile so as to adapt the curvature of the insole in said central part according to the height of the heel by fixing the shapes and relative positions of said guide and retaining means, said guide and retaining means being wrapped by an envelope of flexible material solidly attached to the insole and leaving a passage free for the insertion of the shank into said guide and retaining means, said guide and retaining means and said envelope being concealed by said rear part of the sole.

By the arrangement associating the guide and retaining means directly with the insole, the overthickness, inevitably generated in the central part of the shoe by these means and by the need to install the shank there, is minimised. The covering of these guide and retaining means by the sole makes their presence practically imperceptible, particularly on the edges of the shoe where only the edge of the sole appears, as in a shoe without such means. At the heel also, there is no apparent overthickness and, due to the fact that the sole does not cover the rear part of the insole, the upper edge of the heel comes directly into contact with the upper of the shoe as will be seen later.

An important aspect of the invention is that, unlike the prior art of US2006075662 mentioned above, the insole extends in a continuous manner up to the rear end of the shoe, above the heel, without structural break such as the hinge of said prior art. The result is that no discontinuity of the insole can be felt and therefore comfort is improved. Also, the continuity of the insole ensures a rigidity for it equivalent to the one obtained in a conventional shoe with fixed heel, whilst allowing, as in certain conventional shoes, a certain flexibility of the front part, required for comfortable walking. Also, as will be better seen below, the insole will also have some deformability in its central part, at the level of the plantar arch and therefore at the level of the shank, to allow the adaptation of the curvature to the shape of each shank associated with any of the various heels which can be installed on the shoe.

Unlike the example of US20070256330 described above, the invention associates the shank directly with the insole and not with a member added under it, which allows the aesthetics to be greatly improved as, on the one hand, the overthickness which globally results under the central part of the insole is lower and, on the other hand, what is visible under this central part is quite similar to the appearance of a conventional sole, without the overthicknesses and the notches of the shoe of US20070256330. This aesthetic appearance of the shoe according to the invention is also reinforced by the fact that the heel is attached directly under the insole and not under the rear part of an added member. As will be better understood later, this allows the upper edge of the heel to be placed directly in contact with the shoe upper without having the intermediary layer formed by the rear part of the flexible added member of the above mentioned prior art.

The envelope of flexible material is connected to the insole and, by covering the guide and retaining means, determines a housing accommodating the shank without significant play. The envelope of flexible material thus participates in keeping firmly in place the insole by ensuring a good connection of the guide and retaining means with the insole. It also allows the upper and the sole to be glued to the insole.

By a suitable choice of its constituent material, this envelope can thus itself form the guide and retaining means and, therefore, directly ensure the guide and retaining function of the shank. A guide integrated into said envelope, for example by overmoulding of the envelope on said guide, can also advantageously form said guide and retaining means or additional shank guide means.

According to a particular alternative arrangement, the guide means accommodating the front part of the shank comprise a plurality of guide parts attached to the insole and distributed along the longitudinal direction being spaced in relation to each other, each guide part extending transversally and including a hole having a shape adapted to allow insertion of the shank without play. It is the insertion of the shank into this set of guide parts which leads to the forming of the insole with a curvature corresponding to the curvature adapted to the height of the heel used. The spacing between the guide parts allows their relative pivoting movement required for the adaptation of the curvature of the insole to the longitudinal profile of the shank.

These guide parts are rigid and, as they are fitted without play onto the shank, stiffen the structure and allow the forces of the foot during walking to be distributed over the complete shank which prevents or, at least, limits the twisting of the insole. Also, preferentially, each of the guide parts extends transversally to the longitudinal direction over a major part of the width of the insole, which reinforces the transversal rigidity of the insole thus avoiding a sagging of the edges of the insole on either side of the shank.

According to an additional arrangement, a guide, for example formed of a foil made of thin metal sheet or of a plastic material, can be placed so as to connect the holes of the various guide parts of the insole, the guide determining a passage of internal shape corresponding to the shape of the section of the shank and with sufficient flexibility to adapt to the various curvatures of the insole. This guide notably facilitates the insertion of the shank by a continuous sliding without there being a risk that the front end of the shank abut one of the guide parts.

According to an embodiment variant, the guide and the guide parts can be made of a single plastic part, for example by injection.

According to another variant, the guide parts are made of plastic material overmoulded onto the guide by injection.

According to a complementary arrangement, the envelope of flexible material is overmoulded simultaneously on the guide parts and on the guide.

The envelope of flexible material covering the guide part leaves a free passage for the insertion of the shank in said guide parts, whilst authorising modifications in their relative positions according to the various heel heights and therefore the various possible curvatures. The envelope made of flexible material also participates in ensuring the secure support of the insole by completing the connection of the guide parts with the insole. The flexible material envelope also participates in improving the visual aesthetics of the shoe by covering the guide parts and smoothing their shapes, to provide a smooth bearing surface for the sole.

This envelope can also directly participate in the guiding of the shank between the guide parts if there is no specific guide as stated above.

According to another particular arrangement, the rear part of the insole comprises an attachment assembly to attach the heel, this attachment assembly extending preferentially over an attachment zone of shape and area corresponding to that of the interface between the heel and the insole, the attachment assembly being attached to the insole plumb with the heel and comprising, on the one hand, heel attachment means and, on the other hand, towards the front, a rear guide part comprising a hole with a shape adapted to allow the insertion of the shank and in alignment with the guide means of the central zone of the insole. This attachment assembly, securely attached to the insole, allows the heel to be solidly attached there and thus also ensures a rigid and reliable connection of the heel with the insole. The rear guide part, attached to this assembly, receives without play the shank and is thus connected without play to the other guide parts by said shank. And, as this rear guide part is securely attached to the rear part of the insole, good rigidity is ensured between the heel and the rear and central parts of the insole when the shank is in place.

Preferentially, the attachment assembly comprises:

-   -   a base insert extending substantially along the plane of the         rear part of the insole, covering at least partially said rear         part, and integrating the rear guide part, and     -   a base located under said rear part, securely assembled with the         base insert and clamping between them the insole, the base         bearing heel attachment means.

This embodiment allows the attachment assembly to be easily and securely assembled on the insole whilst also participating in the secure support of the rear of the upper with the insole by clamping the lower edge of said upper between the insole and the edge of the base as will be better seen later.

To be attached under the rear part of the insole, the heel comprises locking means to maintain the assembly with the insole and unlocking means to be able to separate the heel from the insole.

Preferentially, the shank is connected to the heel by a pivot junction with an axis perpendicular to the longitudinal direction and located towards the front of the heel, the pivot junction being arranged in such a way that, after the shank has been inserted into the guide means of the insole, the heel can pivot towards the rear part of the insole until it makes contact under said rear part and simultaneously anchor there, directly or after a complementary sliding movement, thanks to the locking means, whilst restraining a rear end part of the shank in relation to the heel.

According to a particular arrangement to ensure this restraining between heel and shank during the anchoring of the heel under the insole, the shank comprises a front extended part configured to engage with said guide means, and the rear end part of the shank is formed by a tongue which extends towards the rear from the pivot axis and which is arranged so that said tongue is blocked between the heel and the rear part of the insole during the anchoring of the heel on said rear part.

According to a particular embodiment, the locking of the heel on the insole is done, as described previously, directly when the heel is pivoted rearwards and upwards after insertion of the shank into the guide means of the insole. The result is that this locking can practically be done automatically by simply pressing the heel on the ground, simply under the weight of the person using the shoe. In addition, as will be also seen later, due to the restraining of the heel on the rear end of the shank, any play, which could appear during the use of the shoe, between the heel, the shank and the insole, is automatically compensated for by the effect of taking up the play and of complementary locking obtained simply by the weight of the user pressing on the heel.

According to a particular arrangement, the attachment means include at least a stud attached to the attachment assembly and extending downwards, and the heel comprises at least a pivoting locking plate associated with said stud, the locking plate extending along a direction transversal to that of the stud and being returned to a basic position by elastic return means, the locking plate comprising a clearance hole for the stud and being arranged so as to cooperate by over-centering on the stud when said locking plate is inserted on the stud as a result of the pivoting of the heel towards the rear part of the insole. Moreover, the heel comprises an unlocking pusher to pivot the locking plate against the elastic return means and consequently free the stud from its engagement by over-centering with the locking plate.

This mode for assembling and locking the heel on the shoe is especially simple and allows installation and locking by simply pressing on the rear part of the shoe after having installed the heel by insertion of the shank in the guide means as described previously. Also, if play tends to be created during use, it is automatically compensated for as soon as the force resulting alone from the weight of the person on the rear of the shoe tends to approach the heel and the insole. To improve taking up the play still further, a compression membrane made of a compressible material is preferentially placed between the attachment assembly and the heel. By its elastic compressibility, this membrane guarantees that there is no play whilst adapting to the small deformations which may occur between the heel and the insole. In addition, it also ensures a cushioning effect between the heel and the insole.

Advantageously, the shank is pivotally mounted on an attachment plate connected to the heel, with a predetermined play at the pivot axis in the vertical and longitudinal directions, the rear tongue of the shank cooperating with the attachment plate along an oblique bearing plane, and the zone of the front part of the shank located at the rear guide part having an obliqueness in the direction opposite to that of the tongue, in a specific arrangement to ensure the elimination of the play between the shank and the rear guide part. In combination with the compressibility of the compression membrane, this arrangement ensures taking up the complementary play between the heel and the attachment assembly, as will be explained later.

According to another embodiment, the heel is connected to the insole by a sliding guide system of current type, for example dovetailed, and a lock ensures the restraining of the heel after assembly. Locking of the heel on the insole is done then, after the heel has been pivoted rearwards and upwards after insertion of the shank into the guide means of the insole, by sliding the heel forwards, the heel then being guided while sliding substantially parallel to the insole by the guide system.

Other features and advantages of the invention will become apparent on reading the following description of a ladies shoe with an interchangeable high heel in compliance with the invention, and of various variants.

BRIEF DESCRIPTION OF THE DRAWINGS

Make reference to the appended drawings where:

FIG. 1 is a side view of a shoe in compliance with the invention,

FIG. 2 is a perspective view of the shoe, without the upper,

FIG. 3 is a partial longitudinal cross-sectional view of the shoe,

FIG. 4 is a cross-sectional view through line IV-IV of FIG. 3,

FIG. 5 is a cross-sectional view through line V-V of FIG. 3,

FIG. 6 is a cross-sectional view through line VI-VI of FIG. 3,

FIG. 7 is a partial perspective bottom view, without the heel, for a first embodiment of the assembly of the heel on the insole with locking by over-centering,

FIG. 8 is a perspective top view of the heel alone and of the shank for this first embodiment,

FIG. 9 is a partial perspective bottom view, with the heel in place, but where the body of the heel has been removed from the drawing to show the over-centering locking means,

FIG. 10 illustrates the start of the heel installation operation by insertion of the shank into the guide means,

FIG. 11 illustrates the heel pivoting phase after insertion of the shank into the guide means,

FIG. 12 is a detailed cross-sectional view through a longitudinal plane showing the pivot connection of the shank on the heel and the connection and locking of the heel on the insole,

FIG. 13 is a corresponding cross-sectional view,

FIG. 14 illustrates the unlocking of the heel,

FIGS. 15 to 17 illustrate three possible variants for the attachment and over-centering locking means of the heel and unlocking means,

FIG. 18 is a perspective longitudinal cross-sectional view of a second embodiment of the connection of the heel with the insole by a sliding assembly,

FIG. 19 is a cross-sectional view of the lock, showing the dovetail guide of the heel of this second embodiment,

FIGS. 20 to 25 illustrate the successive installation phases of the heel for this second embodiment,

FIGS. 26 to 27 illustrate a complementary variant of the attachment and locking means for the first embodiment.

DETAILED DESCRIPTION

The shoe shown on FIGS. 1 to 3 includes an insole 1 to which the heel 2 and the upper 10 are attached, and a sole 9, attached under the insole, including a front part 91 covering the front part 11 of the insole and intended to come into contact with the ground and a rear part 92 to cover a central part 12 of the insole, located between the front part 11 and the heel 2.

FIG. 4 shows the assembly of the front part 10 a of the upper with the insole 1, the edges 101 of the upper being folded and glued under the front part 11 of the insole and the sole 9 covering the underside of the whole assembly so that the edges 101 are inserted between the insole and the front part 91 of the sole 9.

In the central part, represented by a cross section on FIG. 5, the edges 101 of the central part 10 b of the upper are folded under the envelope 6, which is secured to the central part 12 of the insole and covers the guide parts 51 which are described in more detail below. The rear part 92 of the sole covers the envelope 6 and the edges 101 of the upper.

In the rear part, at the heel, represented by a cross-section on FIG. 6, the edges 101 of the rear part 10 c of the upper are folded under the rear part 13 of the insole and maintained between the insole and a base 31, secured to the insole and intended to accommodate the heel 2, as will be explained below.

As can be clearly seen on FIGS. 1 and 5, the central part 92 of the sole forms only a slight overthickness 921 under the shoe with respect to the edges of said sole, this overthickness 921 existing only in the middle longitudinal part of the shoe, and therefore practically invisible during current use of the shoe, which preserves the aesthetic appearance of the shoe. Also note that, as can be seen on FIGS. 1 and 3, the upper edge 210 of the heel is directly adjacent to the upper 10 c, this also participating in the global aesthetic appearance of the shoe.

The insole 1 typically comprises one or more plates of various thicknesses glued together, comprising in the rear part 13 a cutout arranged to accommodate an attachment assembly 3 comprising a base 31 and a base insert 32, only the latter being visible on FIG. 2 where the shoe is shown without the upper and without the whole length sock. The base insert 32 is flush with the upper face of the insole. The plates forming the insole can be made from a cellulose material, leather, textile, and also from technical materials such as polypropylene. This plate assembly is relatively flexible, similar to that of a conventional insole before the shank is attached there.

As can be seen on FIGS. 8 and 12 to 14, the heel 2 comprises a body 21 with an external shape determined according to the required style, and an attachment plate 22 is attached to the upper face of the heel, for example by screws. The attachment plate 22 is intended to bear against the lower face 311 of the base 31, with insertion of a compression membrane 23 glued to the attachment plate, or to said base. Moreover, the attachment plate 22 accommodates, installed by pivoting along an axis A perpendicular to the longitudinal direction of the shoe, a shank 4 the front part 45 of which, forward of axis A, has an elongated and curved shape, the curvature of the shank being determined to create the curvature of the shoe according to the height of the heel and the size of the shoe. The shank 4 has a cross section of rectangular shape, with the width higher than the height. Its pivoting axis is comprised for example by a mechanical pin 42 fitted into bosses 221 formed on the attachment plate 22. As can be seen on FIG. 12, the hole 41 of the shank through which pin 42 passes has a diameter substantially higher than that of the pin, to ensure a play typically of around 0.5 to 1 mm, allowing the translation movements of the shank in relation to the attachment plate in the plane orthogonal to axis A. Moreover, the shank 4 comprises a rear part in the form of a tongue 43, which extends towards the rear from axis A the inner face 431 of which has a slope, in relation to the longitudinal direction of the shank assembly, adapted to cooperate in contact with a bearing zone 222 of similar slope formed on the attachment plate 22. The zone 46 of the front part of the shank near to axis A is thickened in the direction of the axis in order to also give it a slope 461, with a gradient opposite to that of the tongue 43.

The central part 12 of the insole accommodates guide means for the shank 4, formed by several guide parts 51, four in the example shown, with rectangular holes 511 in their central part of same dimensions as the section of the shank. The guide parts are rigid parts made, for example, from a plastic or metal material, in particular stainless steel or aluminium. They can be made either in the form of a thick part, or a folded sheet metal part. The guide parts extend transversally over a large part of the insole to transversally stiffen the insole and are attached under the insole 1 at a distance from each other, for example by gluing.

The base insert 32 is attached by screws to the base clamping between them the insole. Note that the base comprises, on its sides and its rear edge, a step 313 making, between the base and the insole, a groove capable of accommodating the overthickness formed by the lower edge 101 of the rear part 10 c of the upper, comprising leather, lining and counter, and in pinching the assembly to better maintain the connection between the insole and the upper.

The base insert 32 comprises, on its front edge, a rear guide part 321 in which a rectangular hole 322 is made, in alignment with the holes 511 of the four guide parts 51, to accommodate the shank 4. Note that the height of the hole 322 of this rear guide part is higher than that of the other guide parts to be adapted to the higher height of the shank in the thickened zone 46 comprising the slope 461.

The base insert 32 consists of a folded sheet metal plate 1.5 mm thick or of a part with a thickness of 1.5 mm on its flat part and of 3 mm at the rear guide part 321, made of a plastic material or of metal, in particular stainless steel or aluminium. The base 31 is a thick part made of plastic or of metal such as aluminium the edges 312 of which are chamfered according to a gradient corresponding to that of a complementary chamfer 211 made on the upper edge 210 of the body of the heel 21, to allow a contact and centering between these parts even in the case of wear. The set of guide parts 51 and of the rear guide part 321 can accommodate a guide 512 comprising for example a fine and flexible part, formed of a metallic sheet or foil folded back onto itself, such as shown on FIG. 7, or made of plastic, which is positioned on the inside of the various holes of the guide parts and which then acts as a guide facilitating the insertion of the shank into the successive guide parts.

Moreover, an envelope 6 made of a flexible material, for example polyurethane, is secured under the insole by gluing or by directly moulding in contact with the insole and covers all of the guide parts 51 and 321, leaving clearance for the insertion of the shank 4 into said guide parts. The envelope 6 thus completes the spaces between the various guide parts to complete the retaining of the sole structure. It also allows the edges 101 of the upper to be glued there as shown on FIG. 5. According to the hardness of the chosen material, it is thus possible to adjust the flexibility or the stiffness of the insole. Said envelope 6 can be made by different processes such as injection or casting around the rest of the assembly. The guide 512 mentioned previously can be integrated there or not.

The heel attachment and locking means on the insole comprise, on the one hand, two cylindrical studs 71 securely attached to the attachment assembly 3 by means of screws 72 ensuring the connection of said studs directly with the base insert 32 and, on the other hand, in the heel, two pivoting locking plates 73 associated respectively with each stud and arranged to engage by over-centering onto the studs when the heel is brought into contact under the base 31 of the attachment assembly. For this purpose, elongated orifices 223 are made in the attachment plate 22 opposite the studs 71 to allow their insertion into the heel and each locking plate 73, of rectangular shape, is pivotally mounted by one of its ends in a housing 212 made in the body 21 of the heel, and is held there by a first boss 224, extending from the attachment plate 22 the end of which holds in position, in said housing, the protruding ends of the pivoting pin 732 of the locking plate. Moreover, each locking plate 73 comprises towards its other end a hole 731 with a diameter very slightly higher than that of the stud 71. The locking plate 73 is arranged so that its hole 731 is axially aligned with the associated stud and a spring 74 pushes it upwards into a basic position in abutment against a second boss 225 formed on the attachment plate. It is to be noted that the body 21 of the heel, typically made of a plastic material, can have a plurality of shapes according to the height of the heel and the aesthetics required. However, the internal shapes and the arrangement of the locking elements are the same for all heels liable to be adapted on a same shoe.

During pivoting of the heel towards the base, the studs 71 are inserted into the heel 2 passing via the orifices 223 of the attachment plate 22 and engage in the holes 731 of the locking plates 73 after having pivoted said locking plates. The low thickness of the locking plates and the small play existing between the holes in the locking plates and the studs cause, under the effect of the springs 74, the locking plates 73 to over-center on the studs 71 and lock them in position.

To ensure an efficient over-centring effect and to conserve it over time, the studs and the locking plates are made of a hard material, such as treated stainless steel, avoiding the deterioration, after several operations, of the surface of the studs and the edges of the plates in contact with the studs.

An unlocking button 8 slidingly mounted from front to rear in heel body 21 and returned by a spring 81, comprises two inclined teeth 82 arranged so as to bear on the locking plates 73 to pivot them downwards, as shown on FIG. 12-14, to against the springs 74 when the button is pressed. This pivoting of the locking plates 73 disengages them from the over-centering with the studs 71 and therefore allows the removal of the heel by pivoting it downwards to move it away from the attachment assembly.

A description will now be given of the use of the system for the installation of a heel on the shoe, illustrated on FIGS. 10 and 11.

This installation of the heel starts by the insertion of the shank 4 in the holes 322, 511 provided for this purpose in the guide parts 321, 51. On passing into these guide parts, the shank imposes its shape by imposing a deformation on the insole 1. This deformation is facilitated by the guide 512, between the faces of which the shank can slide without risk of coming into abutment with one of the guide parts.

When the heel arrives in abutment, it suffices to turn the heel around axis A of the shank to place it in locked position under the rear part of the insole, the locking being done automatically by means of the over-centering lock system.

It can be seen that the purpose of the compression membrane 23, made of an elastically deformable thermoplastic material, or of rubber, is notably to allow a flexible contact between the base 31 and the attachment plate 22 of the heel and thus absorb a part of the energy during the impact of the heel on the ground.

In addition, according to the walk of the wearer and the wear, it compresses and therefore reduces the distance between the base 31 and the attachment plate 22; by virtue of this, the compression membrane is a key element of the play reduction mechanism which compensates for the inevitable dimensional dispersions during the industrial manufacture of the parts and the various plays which can result from the natural wear of the locking elements and which could lead to poor stabilisation of the foot and therefore have a negative impact on comfort when walking.

This play reduction system is explained below in relation to FIG. 12. The holding in position of the heel in relation to the insole results in fact from the combination of:

-   -   plane-on-plane contact between the base 31 and the attachment         plate 22 with insertion of the compression membrane 23,     -   conical centering of the base 31 in the upper part of the heel         body 21 thanks to chamfers 312, 211,     -   engagement of the thickened part 46 of the shank 4 in the hole         322 of the guide part 321 formed integrally with the base insert         32,     -   locking of the studs 71, secured to the base 31 and of the base         insert 32, in the locking plates 73 connected to the body 21 of         the heel by the boss 224.

The play reduction system aims therefore in compensating for the risks of play that the combination of these various means can cause. It operates as follows: when the heel is brought by pivoting into its normal position under the rear part of the insole, it bears by the bearing zone 222 on the lower face 431 of the tongue 43, clamping it against the base 31. Thanks to the vertical play between the shank 4 and the pin 42 acting as its pivot axis, this clamping can be done without being hindered by said pin. Moreover, due to the obliqueness of the contact surfaces 431, 222, this clamping tends to push the shank forwards which ensures the insertion of the thickened and bevelled part 46 of the shank into the hole 322 of the rear guide part 321 up to complete abutment of the shank in said guide part 321. This movement of the shank forwards is also allowed thanks to the horizontal play between the shank and the pin 42. This displacement is of course limited but is sufficient to ensure a perfect blocking of the shank in the rear guide part 321 and therefore in relation to the insole. Moreover, this displacement also leads to a corresponding displacement of the attachment plate upwards but, due to the low slope of the contact surfaces 431, 422, this vertical displacement remains low and is compensated for by a compression of the compression membrane 23 to always ensure good flat contact between the attachment plate and the base via said compression membrane. The positional locking is always perfectly ensured by the locking system by over-centering which allows the locking precisely in each relative position between the locking plates and the studs. Also, it can be seen that the play reduction system acts not only at the time the heel is installed but also later, during use, whenever play appears, as it is automatically used as soon as the heel can approach the base, be it only slightly, by the clamping force supplied by the pressure of the foot when walking.

As stated previously, the removal of the heel is done simply by pressing on the unlocking button 8 which pivots the locking plates 73 downwards, thus freeing the studs from their over-centering and allowing the pivoting of the heel downwards. As soon as the studs disengage from out of the orifices 223 of the attachment plate, the heel and the shank can be removed by sliding towards the rear of the shoe.

The locking system described above as an example is not restrictive for the invention. For example, systems also using the locking by over-centring principle can be used but in other configurations, such as, for example, those shown on FIGS. 15 to 17.

The system shown on FIG. 15 uses a single stud 71 a and a single locking plate 73 a extending this time in the longitudinal direction, the unlocking being also controlled by a sliding pusher 8 a arranged to make the locking plate pivot to against a return spring, not shown.

The system shown on FIG. 16 uses two studs and two locking plates 73 b extending in the longitudinal direction, the unlocking being also controlled by a sliding pusher 8 b acting simultaneously on the two locking plates.

The system shown on FIG. 17 also uses a single stud and a single locking plate 73 c also extending in the longitudinal direction but arranged with its pivoting axis towards the rear, the unlocking here being controlled by a pivoting lever 8 c.

Another locking system is again shown on FIGS. 26 and 27. In this case, the locking is no longer ensured by an over-centering system as in the previous examples but by a sliding hook 73 d mounted in the heel sliding parallel to the insole and returned by a spring, the hook 73 d engaging with a locking plate 71 d attached under the base 31.

A second embodiment of the invention, and its use, is illustrated by FIGS. 18 to 25. In this second embodiment, the connection of the heel with the insole is done, after insertion of the shank into the guide means, by a sliding of the heel from rear to front in a slide made on the base of the attachment assembly and locking at end of sliding travel.

The base 31′ comprises a slide 24, for example dovetailed, extending parallel to the plane of the rear part 13 of the insole 1, and the heel 2 comprises a slider 25 adapted to slide in the slide. The locking of the heel is ensured by the engagement of a notched lock 75, vertically slidingly guided in the heel, with corresponding notches 76 made on the lower face of the base 31′. The lock 75 is pressed towards the notches 76 by a spring 77 and an unlocking pusher 85 is arranged to move the lock downwards, by a bevelled system 86, or another equivalent system, and disengage it from the notches 76.

Moreover, the shank is pivotally mounted on the heel by a mechanical pin 42 inserted into a longitudinal opening 47 formed in the shank. As will be seen later, this opening 47 notably allows the shank to be inserted into the guide means of the insole without having to simultaneously exert a force to align the slider 25 of the heel in the slide 24 of the base. Indeed, due to the stresses required to adapt the curvature of the shoe to the curvature of the shank 4, it would be difficult to ensure at the same time, at least at end of travel, the penetration of the shank into the guide means along a curved trajectory and the sliding of the heel along a rectilinear trajectory. The opening 47 therefore first allows the shank to be completely inserted by pushing it into position close to the abutment by means of the heel, then the heel to be brought towards the rear so that it can be placed by pivoting in alignment with the slide and, lastly, to be slid into the slide until it again comes into abutment by the pin at the end of the opening thus ensuring the blocking of the shank and, finally, locks the heel in position on the base.

The successive heel installation steps are shown on FIGS. 20 to 25. First of all, as shown on FIG. 20, the shank 4, pivoted in relation to the heel 2, is brought under the base 31′, then the end of the shank is inserted into the rear guide part 321 (FIG. 21). The shank is then pushed by means of the heel 2 through the rear guide part 321 and the other guide parts 51 secured to the insole, the shape of the heel authorising a grip allowing the required force to be exerted to adapt the curvature of the insole to that of the shank, this force being transmitted from the heel to the shank by the abutment of the pin 42 at the end of the opening 47, as can be seen on FIG. 22.

As the shank is then in a position close to the abutment and already held clamped in the guide parts, the heel is moved towards the rear (FIG. 23) then pivoted to bring it to under the base 31′, in alignment with the slide 24, as shown on FIG. 24.

The heel 2 is then again slid forwards up to abutment and locking by engagement of the lock 75 with the notches 76 of the base (FIG. 25). It can be seen that, by doing this, the pin 42, returned to the bottom of the opening 47, has pushed the shank into final abutment position and maintains it in this position. Also, the rear part 43 of the shank, which comprises a lower inclined face 431, bears on a corresponding inclined face 222′ of the heel, which procures, due to the displacement of the heel forwards, at end of travel, a wedge effect tending to eliminate the plays between the rear part 43 of the shank, the heel and the base.

To remove the heel, it suffices to press on the unlocking pusher 85 which then moves the lock 75 downwards and disengages it from the notches 76 to allow the sliding of the heel rearwards and its removal, together with that of the shank, from the shoe.

The invention is not limited to the embodiments described above only as examples. In particular, the attachment assembly 3 could be made differently, for example in one piece combining the functions of the base, of the base insert and of the rear guide part, the assembly then being securely attached to the insole by any appropriate attachment means, for example by gluing. Also, as stated previously, the individualised guide parts of the example described above could be replaced by equivalent guide and retaining means, integrated into the flexible envelope; also, the guide, the guide parts or other sufficiently stiff guide means and/or the guide, of low thickness to allow its deformation according to the various curvatures, could be made in one piece by moulding, by injection for example, of plastic material. 

1. Shoe with removable heel comprising an insole (1) and an upper (10) attached to the insole, the insole having a flexible central part (12) to adapt its curvature to the height of the heel, a removable heel (2), arranged so that it can be attached under a rear part (13) of the insole and form with said rear part (13) a stiff separable assembly, a sole (9) attached under the insole forward of the heel to cover a front part (11) of the insole and comprising a rear part (92) to cover a central part (12) of the insole located between the front part and the heel, the heel being moreover connected to a shank (4) extending along a longitudinal direction of the insole and engaging without significant play transversally to said longitudinal direction with guide and retaining means (51, 321) located in said central part (12) and secured to the insole, the shank having a predetermined longitudinal profile to adapt the curvature of the insole in said central part according to the height of the heel, said guide and retaining means being wrapped by an envelope (6) made of flexible material securely attached to the insole and leaving a passage free for the insertion of the shank (4) into said guide and retaining means, said guide and retaining means and said envelope being concealed by the rear part (92) of the sole.
 2. Shoe according to claim 1, characterised in that the guide and retaining means receiving the front part of the shank comprise a plurality of guide parts (51, 321) secured to the insole and distributed along the longitudinal direction being spaced in relation to each other, each guide part comprising a hole (511, 322) of shape adapted to allow insertion without play of the shank (4).
 3. Shoe according to claim 2, characterised in that each of the guide parts (51, 321) extends transversally to the longitudinal direction over a major part of the width of the insole (1).
 4. Shoe according to claim 2 or 3, characterised in that a guide (512) connects the holes (511, 322) of the various guide parts of the insole, the guide determining a passage of internal shape corresponding to the shape of the section of the shank (4) and with sufficient flexibility to adapt to the various curvatures of the insole.
 5. Shoe according to claim 4, characterised in that the guide (512) and the guide parts (51, 321) are made in one piece of plastic material.
 6. Shoe according to claim 4, characterised in that the guide parts are made of plastic material overmoulded onto the guide by injection.
 7. Shoe according to any one of the claims 4 to 6, characterised in that the envelope of flexible material is overmoulded onto the guide parts and the guide.
 8. Shoe according to claim 1, characterised in that said guide and retaining means comprise a guide integrated into said envelope, for example by overmoulding of the envelope on said guide, for the guidance of the shank.
 9. Shoe according to claim 1, characterised in that the rear part (13) of the insole comprises an attachment assembly (3) to attach the heel, the attachment assembly being secured to the insole plumb with the heel and comprising, on the one hand, heel attachment means (71; 24,25) and, on the other hand, towards the front, a rear guide part (321) comprising a hole (322) of appropriate shape to allow the insertion of the shank and in alignment with the guide means (51) of the central area (12) of the insole.
 10. Shoe according to claim 9, characterised in that the attachment assembly (3) comprises a base insert (32) extending substantially along the plane of the rear part (11) of the insole, covering, at least partially, said rear part and integrating the rear guide part (321), and a base (31) located under said rear part, securely assembled with the base insert by clamping between them the insole and bearing heel attachment means (71; 24,25).
 11. Shoe according to claim 9, characterised in that the shank (4) is connected to the heel (2) by a pivot connection with an axis (A) located towards the front of the heel, the pivot connection being arranged so that, after the heel (4) has been inserted into the guide means (51, 321) of the insole, the heel can pivot towards the rear part of the insole to come into contact under this rear part and be anchored there, directly following the pivoting or following a complementary sliding movement, thanks to the locking means (71, 73; 75, 76) whilst restraining a rear end part (43) of the shank in relation to the heel.
 12. Shoe according to claim 9, characterised in that the rear end part of the shank is formed of a tongue (43) which extends rearwards from axis (A) of the pivot and which is arranged so that said tongue is blocked between the heel and the rear part of the insole when the heel is anchored on said rear part.
 13. Shoe according to claim 9, characterised in that the attachment means comprise at least one stud (71) secured to the attachment assembly (3) and extending downwards and the heel comprises at least one pivoting locking plate (73) associated with said stud, the locking plate extending along a direction transversal to that of the stud and being returned to a basic position by elastic return means (74), the locking plate comprising a stud clearance hole (731) and being arranged so as to cooperate by over-centring on the stud when said locking plate is inserted onto the stud following the pivoting of the heel towards the rear part of the insole.
 14. Shoe according to claim 13, characterised in that a compression membrane (23) made of a compressible material is located between the attachment assembly (3) and the heel (2).
 15. Shoe according to claim 12, characterised in that the shank (4) is pivotally mounted on an attachment plate (22) attached to the heel, with predetermined play at the pivot axis (A), the rear tongue (43) of the shank cooperating with the attachment plate (22) along a slanted bearing plane (222, 431) and the zone (46) of the front part (45) of the shank located at the rear guide part (321) having an obliqueness (461) in direction opposite to that of the tongue in an arrangement capable of ensuring the elimination of the plays between the shank (4) and the rear guide part to ensure the taking up of the play between the heel and the attachment assembly.
 16. Shoe according to claim 12, characterised in that the heel (2) is connected to the insole (1) by a sliding guide system (24, 25) and a lock (75) ensures the restraining of the heel in relation to the insole after assembly. 